JPH052217A - Liquid crystal panel projection device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display panel projection device can be increased in the apparent number of picture element to twice as large as the conventional number of picture elements and maintains screen brightness at practical level by using inexpensive and bright liquid crystal panels of practical level as they are and providing an optical interface. CONSTITUTION:Liquid crystal panels 7, 12, and 15 which make non-interlaced displays corresponding to field signals of a standard television signal are used as video display carriers and an image is enlarged and projected on a large-sized screen 20 by using a light source 1 and a projection lens 19. An optical interface unit 32 which moves an optical axis vertically on the screen by a specific quantity in parallel in synchronism with the field signals is arranged in the optical path between the liquid crystal panels and projection lens 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel projection device which uses a liquid crystal panel as an image display carrier and projects the displayed image on a large screen by a light source and a projection lens.

[0002]

2. Description of the Related Art In recent years, the progress of liquid crystal display technology has been remarkable, and with the advent of liquid crystal panels excellent in contrast and color reproducibility, a liquid crystal panel projection device for enlarging and projecting on a large screen using a color liquid crystal panel as an image display carrier has been developed. It has been put to practical use. In this type of device, the light from the light source is converged into substantially parallel rays by the converging optical system, the transmissive color liquid crystal panel is irradiated, and the transmitted light is enlarged and projected on the screen through the projection optical system. , The number of pixels of the color liquid crystal panel currently in practical use is 70,000 to 90,000,
When one set of red (R), green (G), and blue (B) pixels is used as one picture element, the number of pixels is one-third, and when projected on a large screen, the roughness of the pixels is noticeable. Therefore, it is not practical.

Therefore, in order to overcome the roughness of the number of picture elements when a liquid crystal panel is used, three black and white liquid crystal panels are used, and light sources of all wavelengths are converted into three color lights of R, G and B in these liquid crystal panels. R, G, and B lights are made incident through a color separation (dichroic) mirror that separates (spectralize), and R, G, and B images are generated by each liquid crystal panel and mixed by a dichroic mirror (mirror method). However, a method of reproducing a color image on a large screen via a projection optical system has been proposed and put into practical use.

FIG. 8 is a schematic diagram showing a conventional example of a liquid crystal panel projection device called a mirror system using a dichroic mirror for color separation and mixing of light. In the figure,
Reference numeral 1 denotes a light source such as a xenon lamp. The light emitted from the light source 1 is reflected by a reflecting mirror 2 that makes the light source light parallel light whose reflection surface is a parabolic surface and is parallel to the optical axis. 1
A condenser lens (not shown) arranged immediately before the lenses 2 and 15 converges the light toward the projection optical system 19. At this time, the converged substantially parallel light rays first enter the blue dichroic mirror 4 that separates and reflects only the blue light. The blue light 5 separated by the blue dichroic mirror 4 is reflected by the mirror 6 in parallel with the optical axis of the converging optical system 3, and the transmissive liquid crystal panel 7 is displayed.
Incident on. A voltage is selectively supplied to the liquid crystal panel 7 according to the constituent pixels of an arbitrary image to be projected, and the blue light 5 transmitted through the liquid crystal panel 7 becomes a blue image light 5a having a video signal.

On the other hand, the blue dichroic mirror 4 loses the blue component 5 and the light transmitted through the mirror 4 becomes yellow. The yellow light 8 is incident on the red dichroic mirror 9, the red light 10 is separated, and the remaining green light 11 is transmitted through the mirror 9. The separated red light 10 enters a transmissive liquid crystal panel 12 having the same structure as the liquid crystal panel 7 and becomes red image light 10a. The blue image light 5a and the red image light 10a are mixed by the mixing dichroic mirror 13 to become magenta color image light 14.

The remaining green light 11 is incident on the transmissive liquid crystal panel 15 having the same structure as the liquid crystal panel 7 to become green image light 11a, which is reflected by the mirror 16 and is incident on the dichroic mirror 17 for mixing. The green image light 11a and the magenta color image light 14 are mixed with the dichroic mirror 1 for mixing.
7 is mixed into the RGB color-mixed mixed image light 18, which is enlarged and projected onto the large screen 20 through the projection optical system 19 to reproduce a color image.

[0007]

By the way, the pixel configuration of the liquid crystal panel used in the liquid crystal panel projection apparatus having the above-described configuration is about 240 pixels in the vertical direction (V) and 400 pixels in the horizontal direction (H). However, both the yield rate and the aperture ratio (brightness) have reached the practical level. On the other hand, the standard television signal system employs an interlaced scanning system, in which one frame constituting one image is divided into an odd field and an even field and transmitted every 1/60 second. There is. Therefore, for the pixel configuration of the liquid crystal panel, no interlace of 240 (V) effective scan lines or interlace of 480 (V) effective scanning lines is selected (an intermediate value cannot be taken). 48
If you select 0 (V) lines, the number of pixels will be 240 (V) at once.
It is twice as much as the above, which causes a significant increase in cost in manufacturing the liquid crystal panel. That is, although efforts are being made to increase the number of pixels in liquid crystal panels at present, as the number of pixels increases, the manufacturing yield increases significantly due to the extreme decrease in yield rate due to pixel defects, and the aperture ratio also decreases. As a result, the luminance decreases, so that 240 (V) lines or more than 400 (H) pixels have not reached the practical level yet, and it takes a lot of effort and time to be put into practical use. There was a problem.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to perform optical interlace scanning by using a liquid crystal panel itself which is inexpensive and bright at a practical level as it is. By doing so, it is an object of the present invention to provide a liquid crystal panel projection device capable of increasing the apparent number of pixels to twice the number of conventional pixels and maintaining the screen brightness at a practical level.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the first invention thereof is to use a liquid crystal panel as an image display carrier and enlarge and project on a large screen by a light source and a projection lens. In the liquid crystal panel projection device, a liquid crystal panel that performs non-interlaced display corresponding to a field signal of a standard television signal, and an optical axis that is arranged in the optical path between the liquid crystal panel and the projection lens and is synchronized with the field signal. And an optical interlacing unit for translating a predetermined amount in parallel.
In a second aspect based on the first aspect, the optical interlacing unit includes an optical flat glass and two predetermined angles corresponding to an odd field and an even field in an optical path of the optical flat glass. And a drive source that reciprocates in synchronization with the field signal. In a third aspect based on the first aspect, the optical interlacing unit comprises an optical flat glass inclined by an angle corresponding to either one of an odd field and an even field, and a field signal for the glass. And a drive source that rotates in synchronism with and moves into and out of the optical path.

[0010]

According to the present invention, the liquid crystal panel displays the odd field and the even field corresponding to the field signal of the standard television signal in a non-interlaced manner. The optical interlacing unit moves the optical axis in parallel in the vertical direction on the screen by an amount corresponding to 1/2 pixel in synchronization with the field signal of the standard television signal. As a result,
The image of the liquid crystal panel which is displayed without interlace with 240 effective scanning lines (in case of 525 interlaced lines) is interlace-scanned on the screen to realize the apparent display of 480 interlaced lines. To be done.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. 1 is a schematic view showing an embodiment of a liquid crystal panel projection apparatus according to the present invention, FIG. 2 is a view showing odd field display and even field display on a screen, and FIG. 3 is a perspective view of an optical interlacing unit. . In the figure, the same components as those in FIG. 8 are designated by the same reference numerals and the description thereof will be omitted. In these drawings, the present embodiment reflects the magenta color image light 14 and reflects the green image light 11a.
The synthesizing dichroic mirror 31 that transmits light is disposed in the optical path between the projection optical system 19 and the mirror 16 and the synthesizing dichroic mirror 13. A race unit 32 is provided, and other configurations are similar to those of the conventional device shown in FIG.

The optical interlacing unit 32 is an optical flat glass 33 arranged in the optical path orthogonal to the optical axis.
And a drive source 34 such as a torque motor for swinging the optical flat glass 33 in the optical path between two predetermined angles corresponding to an odd field and an even field in synchronization with a field signal. There is. Flat glass 3
The plate thickness, the refractive index and the inclination angle θ (see FIG. 4) of 3 are selected so as to obtain the distance Δd required to position the optical axis between the rasters of the projected image. Therefore, if the flat glass 33 is tilted by the angle θ, the mixed color image light 1
Reference numeral 8 transmits and refracts the flat glass plate 33 and translates it by Δd.

In the liquid crystal panel projection apparatus having such a structure, the liquid crystal panels 7, 12 and 15 have a pixel structure of about 240 (V) lines and 400 (H) pixels, and correspond to a field signal of a standard television signal. And display without interlace. At this time, when the flat glass 33 is swung in synchronization with the field signal by the driving source 34 and tilted by a predetermined angle, the optical axis is vertically halved on the screen 20.
The pixels can be moved in parallel by the amount corresponding to the pixels. Therefore,
The number of pixels on the screen 20 can be doubled at once to 240 (V), and an apparent 480 (V) interlaced display can be realized.

FIG. 5 is a diagram showing the relationship between the timing chart of the standard television signal and the inclination of the flat glass 33 and the field synchronizing signal. Reference numeral 40 denotes a vertical deflection signal of the television, which is made up of 525 fields in one frame, of which 263 scanning lines are included in the odd field, 240 effective scanning lines, and 262 scanning lines are included in the even field. Then, the flat glass 33 is operated during the V retrace time (1.5 ms) in synchronization with the field signal each time it switches to the odd and even fields. 4
1 is a field synchronization signal.

FIG. 6 is a perspective view of an optical interlacing unit showing another embodiment of the present invention. In this embodiment, a semi-circular plate 44 is provided with an optical flat glass 33 which is also formed in a semi-circular shape, and the flat glass 33 is applied to the plate 4.
4 is rotated by a driving source 34 such as a step motor, and the flat glass 33 is put into and taken out of the optical path approximately every half rotation. The flat glass plate 33 is inclined with respect to the optical axis by an angle β corresponding to either the odd field or the even field. Even in the optical interlacing unit 32 having such a configuration, when the flat glass 33 is rotated and inserted into the optical path, the optical axis is vertically synchronized on the screen by 1/2 pixel in synchronization with the field synchronization signal. Since it can be moved, the same effect as in the above embodiment can be obtained.

FIG. 7 is a schematic view showing another embodiment of the present invention. In this embodiment, one black and white liquid crystal panel (or color liquid crystal panel) is used, and 46 is a condenser lens and 47 is a black and white liquid crystal panel.

[0017]

As described above, in the liquid crystal panel projection apparatus according to the present invention, the optical interlacing unit is provided in the optical path, and the optical axis is moved vertically on the screen in synchronism with the field signal. Since the race display is performed, the apparent number of pixels can be doubled as compared with the conventional one, and the screen brightness can be sufficiently ensured. Therefore, an inexpensive liquid crystal panel can be used as it is, and the configuration of the optical interlacing unit is simple, so that an inexpensive liquid crystal panel projection device can be provided.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a liquid crystal panel projection device according to the present invention.

FIG. 2 is a diagram showing an odd field display and an even field display on a screen.

FIG. 3 is a perspective view of an optical interlacing unit.

FIG. 4 is a diagram showing the inclination of the flat glass and the movement of the optical axis.

FIG. 5 is a diagram showing a relationship between a timing chart of a standard television signal and the inclination of a flat glass and a field synchronization signal.

FIG. 6 is a perspective view of an optical interlacing unit showing another embodiment of the present invention.

FIG. 7 is a schematic view showing another embodiment of the present invention.

FIG. 8 is a schematic diagram showing a conventional example of a liquid crystal color projection device.

[Explanation of symbols]

1 light source 4, 11 Spectral dichroic mirror 7, 12, 15 LCD panel 13, 17, 31 Synthetic dichroic mirror 32 Optical interlace unit 33 Optical flat glass 34 Drive source

Claims (3)

[Claims] 1. A liquid crystal panel is used as an image display carrier,
In a liquid crystal panel projection device for enlarging and projecting on a large screen by a light source and a projection lens, a liquid crystal panel that displays a non-interlaced display corresponding to a field signal of a standard television signal, and is arranged in the optical path between the liquid crystal panel and the projection lens. And an optical interlacing unit that translates the optical axis by a predetermined amount in synchronization with the field signal. 2. The liquid crystal panel projection apparatus according to claim 1, wherein the optical interlacing unit includes an optical flat glass plate and two optical flat glass plates corresponding to an odd field and an even field in an optical path of the optical flat glass. A liquid crystal panel projection device comprising: a drive source that reciprocates in synchronization with a field signal within a predetermined angle. 3. The liquid crystal panel projection device according to claim 1, wherein the optical interlacing unit is an optical flat glass inclined by an angle corresponding to one of an odd field and an even field, and the glass. A liquid crystal panel projection device comprising: a drive source that rotates the light source in synchronization with a field signal and moves the light source into and out of the optical path.